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Journal of Pediatric Surgery (2013) 48, 1778–1783

Functional urethral obstruction following tubularisedincised plate repair of hypospadiasAhmed T. Hadidi⁎

Hypospadias Clinic, Department of Pediatric Surgery, Emma and Offenbach Hospitals, Offenbach, Germany

Received 13 July 2012; revised 7 October 2012; accepted 19 October 2012

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Key words:Hypospadias;Urethra;Penis;Tubularised incised plate;Complications

AbstractPurpose: To report functional urethral obstruction (FUO) following the tubularised incised plate (TIP)procedure for hypospadias repair and its management.Materials and Methods: Between January 2003 and December 2010, 263 patients were referred withcomplications following TIP repair and who were reviewed on regular follow up after further correction.One hundred and twenty-nine of these patients presented with persistent obstructive voiding signs andsymptoms in spite of apparently successful calibration or dilatation, 32 presented with persistentstenosis, and 97 with recurrent fistula. The mean age at surgery was 2.9 years (range 1–4). Thecomplications were corrected using 1 of 2 techniques: modified Mathieu (112) and lateral onlay flap(17). The mean follow-up was 4 years (range 1–9).Results: The obstructive symptoms were corrected with a single procedure in 120 (93%). Nine patients(7%) developed complications in the form of fistula (7 patients) and glanular dehiscence (2 patients) thatwere corrected successfully in a second operation.Conclusions: The incised urethral plate may heal forming a deep narrow groove resulting in FUO.Patients with FUO present with obstructive voiding symptoms in spite of successful calibration ordilatation. These symptoms disappear after reconstruction of a wide fully epithelised neo-urethra.© 2013 Elsevier Inc. All rights reserved.

During the last decade, the tubularised incised plate (TIP)technique for repair of hypospadias has become a popularprocedure [1]. To my knowledge this is the first report offunctional urethral obstruction (FUO) as a complication ofthe TIP procedure.

For the purpose of the study Functional UrethralObstruction (FUO) is defined as persistent obstructivevoiding symptoms (dysuria, pain and/or persistent straining)

⁎ Max-Planck Str.2, Seligenstadt, D-63500, Germany. Tel.: +49 17405 6905; fax: +49 6182 843 0293.

E-mail addresses: Prof.Hadidi@hypospadiezentrum.de, ahmedtha-idi@yahoo.de.

022-3468/$ – see front matter © 2013 Elsevier Inc. All rights reserved.ttp://dx.doi.org/10.1016/j.jpedsurg.2012.10.071

and/or clinical signs of back pressure (e.g. increased bladderwall thickness, acquired reflux and/or residual urine inbladder after micturition) or recurrent fistula in spite of theability to pass catheter size F8 through the neo-urethra. Thepatients did not have these symptoms and/or signs beforehypospadias repair.

1. Material

The medical records of 375 patients referred betweenJanuary 2003 and December 2010 with complications of

1779Functional urethral obstruction

hypospadias repair were reviewed. Two hundred and sixtythree patients with complications after TIP repair and whohad a further corrective operation and were reviewed on aregular follow up. The remainder had other techniques ofrepair or did not maintain regular follow up.

There were 129 patients who presented with persistentobstructive symptoms; 32 presented with persistentdysuria; and 97 with recurrent fistula. Of the 129 patientswith persistent obstructive symptoms, 112 patients wereborn with distal hypospadias and 17 patients born withproximal hypospadias. One common finding in all the 129patients was the ability to pass a catheter size F 8 throughthe neo-urethra.

The mean age at the time of corrective surgery for thecomplications was 2.9 years (range 1 to 4 years). The meannumber of procedures performed prior to referral, was 2.4

Fig. 1 Functional urethral obstruction: A, Failed TIP showing a skin brbridge shows that incision of the urethral plate heals as a deep groove thatwith contrast injected along the urethra showing the anterior narrow urethurethra (the artefact is dye spilling around the coronal sulcus on the gobstruction where the concertinoed urethra is causing narrowing but theimpression that the urethra is wide. (From: Hadidi AT, Azmy AF (EHeidelberg with permission (in Press).

(range 1 to 4). The time interval between the initial failedrepair and the salvage urethroplasty was more than6 months. The mean follow-up period was 4 years (range1 to 9 years).

The 129 patients with FUO were subdivided into 2groups. Group 1 included 32 patients who had persistentdifficulty with micturition which had not been cured bydilatation although temporary improvement had occurred insome patients. Repeated dilatation had been performed insome every 2 weeks over prolonged periods. Three patientshad a transurethral catheter inserted for more than a monthwithout effecting a cure. One patient was referred with supra-pubic catheter for 5 weeks due to persistent dysuriafollowing TIP repair. Patients in Group 2 (97 patients)presented with dysuria and recurrent fistula after closure asshown (Fig. 1).

idge and urethral stenosis associated with fistula. B. Incision of thedoes not increase the diameter of the neo-urethra. C. Urethrographyra which causes functional narrowing and the more dilated posteriorlans). D. Diagram showing the mechanism of functional urethralinsertion of a firm catheter expands the neo-urethra giving the falseds.) Hypospadias Surgery, 2nd Edition, Springer-Verlag, Berlin

1780 A.T. Hadidi

1.1. Management

Under anaesthesia, the urethral meatus and the availabil-ity and quality of foreskin and penile skin were assessed. Itwas possible to pass a catheter size F8 in all the 129 childrenwith FUO.

The neo-urethra was incised until a normal, wide urethrawas reached. It was found that the urethral plate incision hashealed forming a scarred narrow, deep groove that yieldedtemporarily to dilatation and gave a false impression that theneo-urethra is not narrow. The explanation of this paradox-ical finding is illustrated in Fig. 1.

Patients with distal hypospadias had the Slit LikeAdjusted Mathieu technique (SLAM) [2] employed(Fig. 2). Patients with proximal hypospadias had a LateralBased Onlay foreskin (LABO) [3] flap to construct a neo-urethra (Fig. 3).

The urethroplasty was reconstructed using vicryl 6/0 ona cutting needle in a continuous subcuticular manner [4]around the appropriate catheter according to the calibre ofthe proximal healthy urethra. All distal urethroplasties werecovered with a second protective intermediate layer frompreputial or penile dartos fascia. For patients withcomplicated proximal hypospadias scrotal dartos fasciaand/or tunica vaginalis was the standard second protectivelayer employed.

Distal forms of hypospadias had a transurethral Nelatoncatheter for 3 days. Proximal forms of hypospadias had asingle transurethral silastic catheter for one week.

Fig. 2 Slit like adjusted Mathieu (SLAM) technique for the correctionurethra is incised until a healthy wide urethra is reached and a meatal burethra.

All patients had a standard dressing in the form ofgentamicin local ointment, gauze and adhesive tape thatcompresses the penis, gauze and catheter against the lowerabdominal wall and allows the free mobility of the patient[5]. The dressing was removed at the time of removal ofthe transurethral catheter and the penis was left exposed.If the dressing became wet with urine or soaked withblood, the dressing was changed using the same standarddressing technique.

Broad-spectrum antibiotics (second generation cephalo-sporin) were used for one week in distal forms ofhypospadias and for two weeks in proximal forms.

Follow up protocol included examination after 3 months,12 months and every 2 years till they reach the age of15 years. Mean follow up period was 4 years (range1–9 years). Uroflowmetry was performed in 19 toilet trainedchildren. Peak flow within 2 standard deviations from meanfor age was considered normal.

2. Results

One hundred and twenty patients had satisfactoryoutcome of surgery, 7 patients developed fistula followingthe SLAM technique and 2 patients developed glanularwound dehiscence following the LABO technique. The 9patients with complications were corrected in a single secondoperation. The fistula was closed primarily and a secondlayer from the surrounding fascia was used. The two patients

of narrow urethra after TIP for distal hypospadias. The narrow newased flap is designed to reconstruct a wide fully epithelialised new

Fig. 3 Lateral based onlay (LABO [3]) for correction of complicated proximal TIP. The narrow urethra is incised until a healthy wide urethrais reached. The patient had adequate lateral skin that was sutured to the incised narrow urethra (A to A′). from: Hadidi A T, with permission.

1781Functional urethral obstruction

with glanular dehiscence following LABO technique had ameatal flap for correction. None of the patients hadobstructive voiding symptoms after corrective surgery.

Results were considered satisfactory when the boyachieves an apical slit-like meatus at the tip of the glanspenis, single forward stream, unimpeded voiding, goodcosmesis and no need for secondary surgery for the urethra.Assessment of the results was performed by an independentout-patient nurse.

Uroflowmetry was performed on 19 toilet trained patientspost-operatively. Fifteen patients had uroflow within twostandard deviation of normal. The remaining four patientshave an equivocal or flat uroflow without any symptoms orsigns of obstruction and are being followed. They arecurrently symptom free.

3. Discussion

Incision of the urethral plate was first described by Reddyin 1975 [6], Orkiszewski 1987 [7], Rich 1989 [8] andpopularized by Snodgrass 1994 [9]. The technique hasbecome increasingly popular in recent years partly becauseof the slit-like meatus that can be achieved [1].

The concept behind the TIP technique is that the urethralplate (UP) is a specialised tissue designed for the formationof the urethra and the new urethra should ideally bereconstructed only from the urethral plate. In hypospadias,the (UP) is usually too narrow to reconstruct the new urethra.Therefore, incision of the urethral plate may increase itswidth to reconstruct a wide urethra. Fig. 4 demonstrates the 3possible pathways of healing of the incised urethralplate. Fig. 4A demonstrates the desired pathway of healingafter incision of the urethral plate with a wide new urethra.However, the incised urethral plate may heal as a deepnarrow groove that yields to a sound or a catheter passingthrough the new urethra (Figs. 1 and 4B) or as a linear scarresulting in stenosis (Fig. 4C).

The standard protocol for surgeons dealing with acomplicated hypospadias is to insert a catheter or a probeinside the urethra to ensure that the new urethra is not narrow.

If the TIP has healed with a linear scar and stenosis, the probeor catheter will not pass through and stenosis can be easilyidentified. If the new urethra has healed forming a deep narrowgroove as was the case in 129 patients included in the study(Figs. 1 and 4B), the deep groove will yield to the catheterwhich will pass through and will give the false impression thatthe new urethra is not narrow.After removal of the catheter, thedeep groove will gradually recoil resulting in a narrow passagefor urine and recurrence of fistula or dysuria.

To our knowledge, functional urethral obstruction (FUO)was not reported before. Those patients presented withpersistent pain, dysuria and/or recurrent fistula. Thisphenomenon was first identified in a child with persistentpain and dysuria in spite of frequent calibration and dilatationunder anaesthesia in 2 other centres. Urethrographyconfirmed the passage of the dye through the narrow newurethra. The deep narrow grove was seen clearly afterincision of the narrow urethra.

Is there objective evidence to support the FUO hypoth-esis? Two experimental studies support this hypothesis;

Eassa et al [10] conducted a well designed objective studyon 12 rabbits and made a 3 cm tattoo in the dorsal urethralplate midline before incising the urethral plate. Theymeasured the stretched width between the incised tattooededges followed by tubularisation of the incised urethral plate.The rabbits were sacrificed two weeks later and theymeasured the distance separating the tattoo incision afterhealing and examined sections at this point histologically.The study concluded that the initial width of the midlinerelaxing incision significantly decreased after completeepithelialisation and the average gain in urethral width wasonly 2 mm. Sections of the healed incised plate in rabbitsshowed the typical deep groove seen in children withcomplicated TIP repair presenting with FUO (Fig. 1).

Hafez at al [11] used the same rabbit model to study thehealing after the TIP technique and they could calibrate theneo-urethra up to F12 sounds. The disparity between theconclusions of the two studies can be explained by FUO andshows that “calibration” can be misleading.

Urethrography is an objective investigation to diagnoseFUO pre-operatively. The dye is injected through a catheter

Fig. 4 The 3 possible pathways of healing of the incised urethral plate. A. the incised urethral plate has healed resulting in the formation of awide new urethra. B, the incised urethral plate has healed as a deep narrow groove that yields to a sound or a catheter passing through the newurethra resulting in Functional Urethral Obstruction (FUO). C, the incised urethral plate has healed as a linear scar resulting in urethral stricture.from: Hadidi A T, with permission.

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1783Functional urethral obstruction

F6. This was used in 14 patients early in the study and whenthe diagnosis was uncertain. It was not justified to performbiopsy or expose all patients with persistent pain and dysuriato radiation (for urethrography).

Calibration or cystoscopy is unreliable and may bemisleading as the sound or cystoscope will dilate and openthe deep narrow groove temporarily and will appear as awide shallow groove.

Uroflowmetry is frustrating in children and oftenproduces flat curves despite satisfactory urethroplasty andthe shape of the curve has uncertain significance [12].Therefore, it was not performed pre-operatively as a routinein this study.

Local skin flaps were the first choice for the author. Slit-Like adjusted Mathieu (SLAM) [2] technique gave satisfac-tory functional and cosmetic outcome in 94% of the patientswith complicated distal hypospadias. Lateral Based Onlayflap (LABO) [3] gave satisfactory functional and cosmeticresults in patients with complicated proximal hypospadiasincluded in the study.

This group of patients with FUO did not have persistentchordee or severe scarring and there was adequate local skinto reconstruct a wide neo-urethra and there was no indicationto use grafts or to perform a two stage repair.

References

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[2] Hadidi AT. The slit-like adjusted Mathieu for distal hypospadias.J Pediatr Surg 2012;47:797-801.

[3] Hadidi AT. Proximal hypospadias with small flat glans; The lateralbased onlay (LABO) flap technique. J Pediatr Surg 2012;47:2151-7.

[4] Hadidi AT. Lateral based Flap: A single stage urethral reconstructionfor proximal hypospadias. J Pediatr Surg 2009;44:797-801.

[5] Hadidi AT. Double Y glanuloplasty for glanular hypospadias. J PediatrSurg 2010;45:655-60.

[6] Reddy LN. One stage repair of hypospadias. Urology 1975;5:475.[7] Orkiszewski M. Urethral reconstruction in skin deficit. Urol Pol/Pol

Urology 1987;40:12-5.[8] Rich MA, Keating MA, Snyder HM, et al. “Hinging the urethral plate

in hypospadias meatoplasty. J Urol 1989;142:1551.[9] Snodgrass W. Tubularised incised plate urethroplasty for distal

hypospadias. J Urol 1994;151:464-5.[10] Eassa W, He X, El-Sherbiny M. How much does the midline incision

add to urethral diameter after Tubularied Incised Plate Urethroplasty?An experimental Animal study. J Urol 2011;186:1625-30.

[11] Hafez AT, Herz D, Bagli D, et al. Healing of unstented tubularizedincised plate urehtroplasty; an experimental study on a rabbit model.BJU Int 2003;91:84.

[12] Snodgrass W, Macedo A, Hoebeke P, et al. Hypospadias dilemmas: Around table. J Ped Urol 2011;7:145-57.